I did think of that. I did see I needed to upgrade the jline library, so I updated. So, per my system, I have these libraries and their versions:
ii libjline-java 1.0-2
ii libjline2-java 2.14.6-1
My classpath mimics the jython classpath (from jython --print).
From what you're saying, could it be that someone upstream may have compiled it against 9 and distributed?